Phenomenology from Lattice QCD and Collider Physics

Lead Research Organisation: University of Glasgow
Department Name: School of Physics and Astronomy

Abstract

The Glasgow theory group has a strong reputation in studies of the subatomic world, and pushing forward our understanding of how it works. This is aimed at uncovering the fundamental constituents of matter and the nature of the interactions that operate between them. There are two approaches to this, and we will use both of them. One is to perform very accurate calculations within the theoretical framework of the Standard Model that we believe correctly describes the particles that we have seen so far and the strong, weak and electromagnetic forces of Nature. Discrepancies between these accurate calculations and what is seen in experiments will then point the way to a deeper theory that describes fundamental particle physics more completely. The second method is concerned with what we might see in LHC results, now appearing, if one of the suggested deeper theories is correct. We must make sure that we optimise the analysis of these experiments to learn as much as possible. Accurate calculations in the Standard Model have foundered in the past on the difficult problem of how to handle the strong force. This force is important inside particles that make up the atomic nucleus, the proton and neutron and a host of similar particles called hadrons produced in high energy collisions. The constituents of these particles are quarks, and they are trapped inside hadrons by the behaviour of the strong force. This 'confinement' of quarks makes calculations of the effect of the strong force on the physics of hadrons very challenging. It can be tackled, however, using the numerical techniques of lattice QCD. This method has been tested thoroughly by the Glasgow group in precision calculations of hadron masses and their comparison to experiment, and its current acceptance as a precision tool is based in no small part on their work. Glasgow continues to lead progress and here we propose further, harder calculations that will predict more details of how hadrons decay from one type to another via the weak force. The comparison of accurate results with experiment will allow us to constrain the parameters of the weak force that give rise to violations of symmetry between matter and antimatter. We plan to halve existing errors for these calculations and that will allow us to test the Standard Model very stringently. The Glasgow team will also investigate theories that go beyond the Standard Model and tests of them that can be done with LHC data. For example, we will provide phenomenological studies of possible physics signatures that could be seen at LHC and how they would distinguish between models. This includes studying new particles that would be present in some models with a view to establishing their properties. In particular we will develop methods for studying the physics of top quarks, which will be produced copiously at LHC. The top is the heaviest quark that we have seen, and it provides an exciting window into new physics. Experimental studies in this area are being led by the Glasgow ATLAS group and we will coordinate with them to provide ways of testing top quark properties in detail, including behaviour that could arise in beyond the Standard Model scenarios. We are also developing new methods for increasing the accuracy of how quarks and gluons affect scattering experiments, which is useful for LHC physics, but may in addition lead to insights in other theories besides QCD. The next four years will be a very exciting time for theoretical particle physics and Glasgow aims to be at the forefront of this work.

Publications


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Antonelli M (2010) Flavor physics in the quark sector in Physics Reports

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Antonelli M (2010) Flavor physics in the quark sector in Physics Reports

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Artoisenet P (2008) Upsilon production at Fermilab Tevatron and LHC energies. in Physical review letters

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Artoisenet P (2009) J/psi production at HERA. in Physical review letters


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Athron P (2009) Constrained exceptional supersymmetric standard model in Physical Review D

 
Description We have performed a number of ground-breaking computations of the properties of hadrons from the theory of the strong interaction along with studies of signals at the Large Hadron Collider that can be used to test the Standard model of particle physics.
Exploitation Route Our findings are regularly used by experimental particle physicists and other theoretical particle physicists in their analyses and for their calculations.
Sectors Education
URL http://www.physics.gla.ac.uk/ppt
 
Description White's work on gravity led to a realisation that the action of a type of refracting sheet (a generalised confocal lenslet array) could be described using the language of metric tensors and differential geometry. This has simplified the design of new optical devices, including spectacles for retinal disorders. Ongoing work with Durham and Sunderland Eye Infirmary may lead to commercialisation.
First Year Of Impact 2014
Sector Manufacturing, including Industrial Biotechology
Impact Types Economic
 
Description Deisa Extreme Computing Initiative
Amount £100,000 (GBP)
Organisation European Commission (EC) 
Sector Public
Country European Union (EU)
Start 10/2010 
End 05/2011
 
Description High Performance Computing Grant
Amount £500,000 (GBP)
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom of Great Britain & Northern Ireland (UK)
Start 11/2009 
End 10/2012
 
Description HPQCD collaboration 
Organisation University of Cambridge
Department Department of Applied Mathematics and Theoretical Physics (DAMTP)
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Academic/University 
PI Contribution We did the numerical simulations
Collaborator Contribution We have done numerical simulations of QCD using information provided from the mathematical calculations done in Cambridge
Impact several publications and grants for computer time in the USA.
 
Description particle physics masterclass 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact The particle physics masterclass runs very year - typically around 130 pupils from 30 schools across
Scotland attend. The class acts as an introduction to particle physics for pupils about to apply to university.
Year(s) Of Engagement Activity 2012,2013,2014,2015